LoongArch: Save and restore CSR.CNTC for hibernation

Save and restore CSR.CNTC for hibernation which is similar to suspend.

For host this is unnecessary because sched clock is ensured continuous,
but for kvm guest sched clock isn't enough because rdtime.d should also
be continuous.

Host::rdtime.d = Host::CSR.CNTC + counter
Guest::rdtime.d = Host::CSR.CNTC + Host::CSR.GCNTC + Guest::CSR.CNTC + counter

so,

Guest::rdtime.d = Host::rdtime.d + Host::CSR.GCNTC + Guest::CSR.CNTC

To ensure Guest::rdtime.d continuous, Host::rdtime.d should be at first
continuous, while Host::CSR.GCNTC / Guest::CSR.CNTC is maintained by KVM.

Cc: stable@vger.kernel.org
Signed-off-by: Xianglai Li <lixianglai@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

diff --git a/arch/loongarch/kernel/time.c b/arch/loongarch/kernel/time.c
index e2d3bfeb6366432ea8df08c4a28002e5af5dbdad..bc75a3a69fc8d55300dfe9d0dec7f8d0ca32f0b0 100644 (file)
--- a/arch/loongarch/kernel/time.c
+++ b/arch/loongarch/kernel/time.c
@@ -111,7 +111,7 @@ static unsigned long __init get_loops_per_jiffy(void)
        return lpj;
 }
 
-static long init_offset __nosavedata;
+static long init_offset;
 
 void save_counter(void)
 {

diff --git a/arch/loongarch/power/hibernate.c b/arch/loongarch/power/hibernate.c
index 1e0590542f987cd59c0bad22f938b51ad0e4f2a5..e7b7346592cb2a335c64ff23a5b2389cf63f6bf7 100644 (file)
--- a/arch/loongarch/power/hibernate.c
+++ b/arch/loongarch/power/hibernate.c
@@ -2,6 +2,7 @@
 #include <asm/fpu.h>
 #include <asm/loongson.h>
 #include <asm/sections.h>
+#include <asm/time.h>
 #include <asm/tlbflush.h>
 #include <linux/suspend.h>
 
@@ -14,6 +15,7 @@ struct pt_regs saved_regs;
 
 void save_processor_state(void)
 {
+       save_counter();
        saved_crmd = csr_read32(LOONGARCH_CSR_CRMD);
        saved_prmd = csr_read32(LOONGARCH_CSR_PRMD);
        saved_euen = csr_read32(LOONGARCH_CSR_EUEN);
@@ -26,6 +28,7 @@ void save_processor_state(void)
 
 void restore_processor_state(void)
 {
+       sync_counter();
        csr_write32(saved_crmd, LOONGARCH_CSR_CRMD);
        csr_write32(saved_prmd, LOONGARCH_CSR_PRMD);
        csr_write32(saved_euen, LOONGARCH_CSR_EUEN);